Lubricants comprise a variety of compounds selected for desirable characteristics such as anti-wear and anti-friction properties. Often commercial lubricants are compositions containing a lubricant base such as a hydrocarbon oil or grease, to which is added numerous lubricant additives selected for additional desirable properties. Lubricant additives may enhance the lubricity of the lubricant base and/or may provide anti-wear or other desirable characteristics.
Lubricants are used in enormous quantities. For example, more than four billion quarts of crankcase oil are used in the United States per year. However, many lubricants currently in use also have undesirable characteristics. Currently available crankcase oils generally include the anti-wear additive zinc dialkyldithiophosphate (ZDDP), which contains phosphorous and sulfur. Phosphorous and sulfur poison catalytic converters causing increased automotive emissions. It is expected that the EPA eventually will mandate the total elimination of ZDDP or will allow only extremely low levels of ZDDP in crankcase oil. However, no acceptable anti-wear additives to replace ZDDP in engine oils are currently available.
Additionally, lubricant bases used in conventional lubricants usually have lubricant additives added to them to improve lubricity. Many of these lubricant additives do not provide sufficient additional lubricity and/or possess additional undesirable characteristics.
Accordingly, it is an object of the present invention to provide environmentally-friendly anti-wear additives for lubricants, wherein the amounts of phosphorous and sulfur in the anti-wear additive are significantly reduced and approach zero. It is another object of the present invention to produce compounds with desirable anti-wear and anti-friction characteristics.